Tooling assembly and associated system and method for manufacturing a porous composite structure

ABSTRACT

A tooling assembly for manufacturing a porous composite structure. The tooling assembly includes a first tooling member and a second tooling member. The first tooling member includes a first body that defines a first internal volume and a first inlet. The first inlet is fluidly coupled with the first internal volume. The first tooling member also includes a first tooling surface that defines a plurality of first perforations that are fluidly coupled with the first internal volume. The second tooling member includes a second body that defines a second internal volume and a second inlet. The second inlet is fluidly coupled with the second internal volume. The second tooling member also includes a second tooling surface that defines a plurality of second perforations that are fluidly coupled with the second internal volume.

FIELD

This application relates to porous composite structures and, moreparticularly, to a tooling assembly, system and method for manufacturingporous composite structures.

BACKGROUND

Acoustically treated composite structures reduce sound by scattering orabsorbing sound energy. Due to this sound attenuating capability,acoustically treated composite structures have been used in variousindustries, including the aerospace industry. For example, acousticallytreated composite structures are commonly incorporated into bypass gasturbine aircraft engines, such as into the inlet inner barrels, fan ductwalls and/or exhaust nozzles, to attenuate the noise associated withhigh volume airflows.

Conventional acoustically treated composite structures include sandwichstructures having a septumized honeycomb core, a perforated facesheetand an impermeable facesheet. The perforations defined by the perforatedfacesheet fluidly couple the cavities of the septumized honeycomb corewith the ambient environment. Therefore, when air flows across theperforated facesheet, the cavities in the core act as Helmholtzresonators and attenuate the sound of the associated airflow. Morespecifically, core walls between adjacent cavities in the core act asacoustic septa to attenuate the sound of the airflow.

Septumized honeycomb cores, however, are expensive and processes forbonding facesheets to the cores can require multiple cure cycles.Further, current processes for perforating composite structures aretypically time-intensive and are associated with high material costs.For example, abrasive perforation can have a significant cycle time,have complex tooling, and/or require a considerable amount of cleanup.Mechanical drilling can have a significant cycle time, have a recurringcost of drill bit replacements, and/or result in the cutting of fibers(which diminishes the strength of the facesheet). Drilling cycle timecan be extensive for large acoustic panels with millions ofperforations. Plastic pin mats can also be used to create perforations,but they are non-reusable and are thus formed to contour and trimmed tosize for one-time usage.

Accordingly, those skilled in the art continue with research anddevelopment in the field of acoustically treated composite structures.

SUMMARY

Disclosed is a tooling assembly for manufacturing a porous compositestructure. The tooling assembly includes a first tooling member and asecond tooling member configured to hold a green layup, a fluid movementdevice configured to move fluid through the layup, and a manifold systemconfigured to distribute the fluid as the fluid moves through the layup.

Also disclosed is a tooling assembly that includes a first toolingmember and a second tooling member. The first tooling member includes afirst body that defines a first internal volume and a first inlet. Thefirst inlet is fluidly coupled with the first internal volume. The firsttooling member also includes a first tooling surface that defines aplurality of first perforations that are fluidly coupled with the firstinternal volume. The second tooling member includes a second body thatdefines a second internal volume and a second inlet. The second inlet isfluidly coupled with the second internal volume. The second toolingmember also includes a second tooling surface that defines a pluralityof second perforations that are fluidly coupled with the second internalvolume.

Also disclosed is a system for manufacturing a porous compositestructure. The system includes a tooling assembly having a first toolingmember and a second tooling member. The first tooling member includes afirst body that defines a first internal volume and a first inlet. Thefirst inlet is fluidly coupled with the first internal volume. The firsttooling member also includes a first tooling surface that defines aplurality of first perforations that are fluidly coupled with the firstinternal volume. The second tooling member includes a second body thatdefines a second internal volume and a second inlet. The second inlet isfluidly coupled with the second internal volume. The second toolingmember also includes a second tooling surface that defines a pluralityof second perforations that are fluidly coupled with the second internalvolume. The system further includes a layup positioned between the firsttooling surface of the first tooling member and the second toolingsurface of the second tooling member.

Also disclosed is a method for manufacturing a porous compositestructure.

In one example, the disclosed method includes positioning a green layupbetween a first tooling surface and a second tooling surface, whereinthe first tooling surface includes a plurality of first perforations andthe second tooling surface includes a plurality of second perforations,and establishing a flow of fluid through the plurality of firstperforations, through the layup, and through the plurality of secondperforations.

In another example, the disclosed method includes positioning a layupbetween the first tooling surface of the first tooling member of atooling assembly and the second tooling surface of the second toolingmember of the same tooling assembly. The first tooling member includes afirst body that defines a first internal volume and a first inlet. Thefirst inlet is fluidly coupled with the first internal volume. The firsttooling member also includes a first tooling surface that defines aplurality of first perforations that are fluidly coupled with the firstinternal volume. The second tooling member includes a second body thatdefines a second internal volume and a second inlet. The second inlet isfluidly coupled with the second internal volume. The second toolingmember also includes a second tooling surface that defines a pluralityof second perforations that are fluidly coupled with the second internalvolume. The method further includes establishing a flow of fluid fromthe first tooling member into the second tooling member wherein thefluid flows through the first perforations, through the layup andthrough the second perforations.

Also disclosed is a method for forming a plurality of tortuous paths ina green layup that includes a plurality of plies, each ply of theplurality of plies including reinforcing fibers embedded in a resinmatrix, the method including (1) supporting the layup and (2) while thelayup is supported, flowing fluid through the layup to displace at leastsome of the resin matrix, thereby forming said plurality of tortuouspaths in the layup.

Various examples of the disclosed tooling assembly, system, method formanufacturing a porous composite structure, and method for forming aplurality of tortuous paths in a green layup will become apparent fromthe following detailed description, the accompanying drawings and theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one example of the disclosed toolingassembly;

FIG. 2 is a side elevational view, in cross-section, of the toolingassembly of FIG. 1;

FIG. 3A is a top plan view of a first tooling member of the toolingassembly of FIG. 1;

FIG. 3B is a perspective view of the first tooling member of FIG. 3A;

FIG. 3C is a perspective sectional view of the first tooling member ofFIG. 3B;

FIG. 4A is a top plan view of a second tooling member of the toolingassembly of FIG. 1;

FIG. 4B is a perspective view of the second tooling member of FIG. 4A;

FIG. 4C is a perspective sectional view of the second tooling member ofFIG. 4B;

FIG. 5 is a side elevational view, in cross-section, of one example ofthe disclosed system for manufacturing a porous composite structure;

FIG. 6 is an exploded perspective view of a plurality of plies of thesystem of FIG. 5;

FIG. 7 is a schematic side elevational view depicting the flow of fluidthrough the system of FIG. 5;

FIG. 8A is a perspective view of a first tooling member in accordancewith another example of the disclosed tooling assembly;

FIG. 8B is a side sectional view of a portion of the first toolingmember of FIG. 8A;

FIG. 9 is a flow diagram of one example of the disclosed method formanufacturing a porous composite structure;

FIG. 10 is a flow diagram of an aircraft manufacturing and servicemethodology; and

FIG. 11 is a block diagram of an aircraft.

DETAILED DESCRIPTION

The following detailed description refers to the accompanying drawings,which illustrate specific examples described by the disclosure. Otherexamples having different structures and operations do not depart fromthe scope of the present disclosure. Like reference numerals may referto the same feature, element, or component in the different drawings.

Illustrative, non-exhaustive examples, which may be, but are notnecessarily, claimed, of the subject matter according the presentdisclosure are provided below. Reference herein to “example” means thatone or more feature, structure, element, component, characteristicand/or operational step described in connection with the example isincluded in at least one embodiment and/or implementation of the subjectmatter according to the present disclosure. Thus, the phrases “anexample,” “some examples,” and similar language throughout the presentdisclosure may, but do not necessarily, refer to the same example.Further, the subject matter characterizing any one example may, but doesnot necessarily, include the subject matter characterizing any otherexample.

Referring to FIG. 1, illustrated is a perspective view of a toolingassembly 30 constructed in accordance with an example. The toolingassembly 30 includes a first tooling member 10 opposed from a secondtooling member 20. Both the first tooling member 10 and the secondtooling member 20 may be similarly sized and shaped to evenly correspondwith one another.

Referring to FIGS. 2, 3A and 3B, the first tooling member 10 includes afirst body 11 that defines a first internal volume 12 and a first inlet13. The first inlet 13 is fluidly coupled with the first internal volume12. The first tooling member 10 also includes a first tooling surface 14that defines a plurality of first perforations 15. The plurality offirst perforations 15 are also fluidly coupled with the first internalvolume 12. As such, the first inlet 13 is in fluid communication withthe plurality of first perforations 15 through the first internal volume12. In some examples, the first tooling surface 14 may be integral withthe first body 11. In other examples, the plurality of firstperforations 15 may be uniformly distributed across the first toolingsurface 14.

Still referring to FIG. 2, but further in reference to FIGS. 4A and 4B,the second tooling member 20 includes a second body 21 that defines asecond internal volume 22 and a second inlet 23. The second inlet 23 isfluidly coupled with the second internal volume 22. The second toolingmember 20 also includes a second tooling surface 24 that defines aplurality of second perforations 25. The plurality of secondperforations 25 are also fluidly coupled with the second internal volume22. As such, the second inlet 23 is in fluid communication with theplurality of second perforation 25 through the second internal volume22. In some examples, the second tooling surface 24 may be integral withthe second body 21. In other examples, the plurality of secondperforations 25 may be uniformly distributed across the second toolingsurface 24 such that they correspond with the plurality of firstperforations 15.

Optionally, the first body 11 may define a first alignment feature 17and the second body 21 may define a second alignment feature 27. Thesecond alignment feature 27 may be sized and shaped to correspond withthe first alignment feature 17. The first alignment feature 17 and thesecond alignment feature 27 may include, for example, ridges, notches orthe like that encourage level and/or secure engagement between the firsttooling member 10 and the second tooling member 20.

A manifold system may be incorporated into or used in conjunction withthe tooling assembly 30. The manifold system may include one or moremanifolds. Turning now to FIG. 3C, which illustrates one example, thefirst tooling member 10 may include a first manifold 16 contained withinthe first internal volume 12. The first manifold 16 may be integral withthe first body 11 (e.g., the first manifold 16 and the first body 11 maybe a single monolithic body) and may include a primary channel 40 with aplurality of secondary channels 41 extending from the primary channel40. In some examples, the secondary channels 41 may extend generallyperpendicular relative to the primary channel 40. Further, this primarychannel 40 may extend from, and be fluidly coupled with, the first inlet13.

As shown by arrow 91 in FIG. 3B, a fluid may flow into the first toolingmember 10 through the first inlet. As shown by arrows 92 and 93 in FIG.3C, the fluid may then travel along the primary channel 40 and divideamongst the secondary channels 41. As shown by arrow 94 in FIG. 3B, thefluid may subsequently exit the first tooling member by flowing throughthe plurality of first perforations 15. In this way, the first manifold16 distributes the fluid across the first internal volume 12 before thefluid flows through the plurality of first perforations.

Turning now to FIG. 4C, the second tooling member 20 may include asecond manifold 26 contained within the second internal volume 22. Thesecond manifold 26 may be integral with the second body 21 (e.g., thesecond manifold 26 and the second body 21 may be a single monolithicbody) and may include a primary channel 40 with a plurality of secondarychannels 41 extending from the primary channel 40. In some examples, thesecondary channels 41 extend generally perpendicular relative to theprimary channel 40. Further, this primary channel 40 may extend from,and be fluidly coupled with, the second inlet 23.

As shown by arrow 96 in FIG. 4B, fluid flowing from the first toolingmember 10 may pass through the plurality of second perforations 25. Asshown by arrows 97 and 98 in FIG. 4C, the fluid may then be received bythe secondary channels 41 and accumulate in the primary channel 40. Asshown by arrow 99 in FIG. 4B, the accumulated fluid may subsequentlyflow out of the second tooling member 20 through the second inlet 23. Inthis way, the second manifold 26 collects the fluid after the fluid hasflowed through the plurality of second perforations 25.

In one particular implementation, the first tooling member 10 contains afirst manifold 16 and the second tooling member 20 contains a secondmanifold 26. Those skilled in the art would appreciate that in thisimplementation, the two manifolds enable the even distribution of fluidacross the first tooling surface 14 and the second tooling surface 24 asthe fluid flows from the first tooling member 10 to the second toolingmember 20.

As shown in FIGS. 8A and 8B, the first tooling surface 14 of the firsttooling member 10 may have intricate, contoured shapes, while stillincluding the first perforations 15. These intricate, contoured shapesmay correspond to the desired shape of a finished porous compositestructure. In one specific, non-limiting example, the first toolingsurface 14 may have a cylindrical shape. In another specific,non-limiting example, the first tooling surface 14 may have a truncatedcone shape. Those skilled in the art will appreciate that the secondtooling surface 24 (FIG. 1) may have a contoured shapes closelycorresponding to the contoured shape the first tool surface 14.

Referring to FIG. 5, illustrated is an example system 300 formanufacturing a porous composite structure. The system includes thetooling assembly 30 of FIG. 1 and a layup 50, which may be green/uncured(i.e., a green layup), positioned between the first tooling surface 14of the first tooling member 10 and the second tooling surface 24 of thesecond tooling member 20.

The system may include a sealing member 60 that overlaps portions of thefirst tooling member 10 and the second tooling member 20. Onceoverlapped, the sealing member 60, the first tooling member 10 and thesecond tooling member 20 may define an airtight vacuum chamber 61 withinwhich the layup 50 may be positioned and a flow of fluid (arrows 95 inFIG. 7) through the layup 50 may be established. The sealing member 60may comprise at least one of a sealant tape and a vacuum bag. Thoseskilled in the art will appreciate that other methods of sealing may beused without departing from the scope of the present disclosure.

Still referring to FIG. 5, the system 300 may include a fluid source 80.The fluid source 80 may be, for example, atmospheric air or an inert gassuch as pressurized nitrogen. The fluid source 80 may be fluidly coupledwith the first inlet 13 of the first tooling member 10. A first fluidline 18 may be used to connect the fluid source 80 to the first inlet 13and a first coupling 19 may be used to securely attach the first fluidline 18 to the first inlet 13.

The system 300 may include a fluid movement device. Still referring toFIG. 5, the fluid movement device may include a vacuum source 70. Thevacuum source 70 may be fluidly coupled with the second inlet 23 of thesecond tooling member 20. A second fluid line 28 may be used to connectthe vacuum source 70 to the second inlet 23 and a second coupling 29 maybe used to securely attach the second fluid line 28 to the second inlet23.

In one particular implementation, the system 300 contains both a fluidsource 80 and a vacuum source 70. Those skilled in the art wouldappreciate that in this implementation, the vacuum source 70 pulls fluidfrom the fluid source 80 which thereby establishes a flow of fluidthrough the system 300 (e.g., arrows 91-99 as shown in FIGS. 3B, 3C, 4B,4C and 7).

Optionally, the fluid movement device may include a blower system influid communication with the fluid source 80. The blower system mayintroduce fluid into the tooling assembly 30 and establish a flow offluid therein. In one example, the blower system may be used inconjunction with the vacuum source 70. In another example, the blowersystem may be used as an alternative to the vacuum source 70.

Optionally, the system 300 may also include a recirculation system forrecapturing fluid once the fluid has flowed through the tooling assembly30. The recirculation system may be in fluid communication with thevacuum source 70 and may further include a resin trap for filtering therecaptured fluid before the recaptured fluid is reintroduced back intothe fluid source 80.

Optionally, a sensor 33, such as a pressure sensor, a flowmeter or thelike, may be positioned on or near the first fluid line 18 to sense thefluid within the first fluid line 18 and/or a sensor 35, such as apressure sensor, a flowmeter or the like, may be positioned on or nearthe second fluid line 28 to sense the fluid within the second fluid line28 The sensors 33, 35 may provide an indication as to whether fluid isflowing (Block 260 in FIG. 9) through the layup 50 as the layup 50 isbeing heated (Block 270 in FIG. 9) to cure (or consolidate) the layup50.

The layup 50 may generally be composed of multiple plies 51. The layupmay also be connected to a core layer 56. For example, the layup 50 mayinclude three plies 51. In another example, the layup 50 may includemultiple plies 51 laid on top of a core layer 56 (e.g., honeycomb). Inyet another example, there may be multiple plies 51 laid on both majorsides of a core layer 56 (e.g., a sandwich structure). Those skilled inthe art will appreciate that other composite materials and layuparrangements may be utilized without departing from the scope of thepresent disclosure.

As shown in FIGS. 6 and 7, one suitable type of ply 51 for use in thelayup 50 is prepreg, i.e., reinforcing fibers 52 embedded in a resinmatrix 53. The resin matrix 53 may comprise a thermosetting resin or athermoplastic resin. Further, the individual plies 51 may be stacked invarying orientations as defined by their reinforcing fibers. As shown inFIG. 6, one ply may by laid in a 0°-90° first fiber orientation 54 andanother ply may be laid in a −45°-45° second fiber orientation 55,resulting in the first fiber orientation 54 being approximately 45°offset from the second fiber orientation 55.

As shown in FIG. 5, a fairing bar 57 may also be positioned between thefirst tooling member 10 and the second tooling member 20. The fairingbar 57 may be approximately equal to the cross-sectional thickness ofthe layup 50 and may fit around the perimeter of the layup 50 whenpositioned between the first tooling member 10 and the second toolingmember 20. When the tooling assembly 30 is used with a vacuum source 70,the vacuum source 70 establishes a pressure differential across thelayup 50. A fairing bar 57 positioned between the first tooling member10 and the second tooling member 20 would prevent the layup 50 frombeing crushed. Those skilled in the art will appreciate that differentfairing bars may be used throughout the manufacturing process toaccommodate changes in the layup 50 as it becomes a porous compositestructure or to account for any additional plies that may be added toit. Those skilled in the art will also appreciate that there may beinstances in which a fairing bar is not needed.

Still referring to FIG. 5, the system 300 may further include aninsulated chamber 100 that the tooling assembly 30 containing the layup50 may be placed within. The insulated chamber 100 may heat the toolingassembly 30 and thereby cure the layup 50. As such, pores may be createdin the layup 50 using the tooling assembly 30 while curing in theinsulated chamber 100. The insulated chamber 100 may comprise at leastone of an oven and an autoclave.

Referring to FIG. 7, by flowing fluid through the first perforations 15,through the layup 50 and through the second perforations 25, the fluiddisplaces resin matrix 53 located between the reinforcing fibers 52 ofeach ply 51, thereby creating pores in the layup 50. It is contemplatedthat the displaced resin matrix may be shifted around each ply orbetween them to accommodate the flow of fluid (arrows 95 in FIG. 7). Itis also contemplated that the displaced resin matrix may becomedislodged and be carried along with the flow of fluid (arrows 95 in FIG.7). The displaced resin matrix may be deposited in the core layer 56,the second tooling member or may be carried into the vacuum source.

Further, due to the nonuniform positioning of the reinforcing fibers 52,the path created by the fluid through the layup 50 is defined by itstortuosity. Without being limited to any particular theory, it isbelieved that such tortuous paths enable the porous composite structureto attenuate sound. It is further believed that a porous compositestructure manufactured according to the present disclosure can exhibitan acoustic resistance substantially equal to traditional drilledfacesheets bonded to a septumized honeycomb core layer 56. In contrastto the perforations in traditional drilled facesheets, the pores createdin accordance with the present disclosure will not be as straight norwill they have a uniformly circular cross section.

Referring to FIG. 9, disclosed is a method, generally designated 200,for manufacturing a porous composite structure using the toolingassembly 30 of FIG. 1. As shown at Blocks 210 and 220, a layup 50, whichmay be green/uncured (i.e., a green layup), is provided and thenpositioned between the first tooling surface 14 of the first toolingmember 10 and the second tooling surface 24 of the second tooling member20. The first tooling member 10 and the second tooling member hold thelayup in a fixed position and help to prevent any bending or distortionthat may occur in the layup 50 during the manufacturing process. A flowof fluid is then established (Block 260) from the first tooling member10 into the second tooling member 20 wherein the fluid flows (Blocks262-264) through the first perforations 15, through the layup 50, andthrough the second perforations 25 (e.g., arrows 94 and 96 in FIGS. 3B,4B and 7).

As shown in Blocks 230 and 240, the first inlet 13 of the first toolingmember 10 may be connected to a fluid source 80 and the second inlet 23of the second tooling member 20 may be connected to a vacuum source 70.In this way, the vacuum source 70 may be used to establish a flow offluid from the fluid source 80 (e.g., arrows 91-99 as shown in FIGS. 3B,3C, 4B, 4C and 7). Those skilled in the art will appreciate that othermethods of establishing a flow of fluid may be used without departingfrom the scope of the present disclosure. Those skilled in the art willalso appreciate that the order of connecting a fluid source 80 and avacuum source 70 is interchangeable.

Referring to Block 250, the tooling assembly 30 may be sealed prior tothe step (Block 260) of establishing the flow of fluid (e.g., arrows91-99 as shown in FIGS. 3B, 3C, 4B, 4C and 7). Sealing the toolingassembly 30 may prevent outside fluid from entering the system 300 whichmay diminish the unidirectional flow of fluid through the layup 50.

Turning now to Block 260, the step of establishing a flow of fluid mayfurther include the step (Block 261) of distributing the fluid prior toflowing the fluid through the first perforations 15 (e.g., arrows 91-94in FIGS. 3B and 3C) and the step (Block 265) of collecting the fluidafter the fluid has flowed through the second perforations 25 (e.g.,arrows 96-99 in FIGS. 4B and 4C). In one expression, the fluid isdistributed using a first manifold 16 contained within the firstinternal volume 12 of the first tooling member 10. In anotherexpression, the fluid is collected using a second manifold 26 containedwithin the second internal volume 22 of the second tooling member 20. Inyet another expression, the fluid is distributed using a first manifold16 contained within the first internal volume 12 of the first toolingmember 10 and then collected using a second manifold 26 contained withinthe second internal volume 22 of the second tooling member 20. Thoseskilled in the art will appreciate that other methods, devices orstructures may be used to distribute and/or collect the fluid withoutdeparting from the scope of the present disclosure.

Referring now to Block 270, the layup 50 is heated concurrently with thestep (Block 260) of establishing the flow of fluid (e.g., arrows 91-99as shown in FIGS. 3B, 3C, 4B, 4C and 7). In other words, the heating(Block 270) occurs simultaneously with the step (Block 260) ofestablishing the flow of fluid. The heating step (Block 270) may occurby placing the tooling assembly 30 into an insulated chamber 100, suchas an oven or an autoclave, and heating the tooling assembly 30 to apredetermined temperature while fluid is flowing (Block 260) through thelayup 50. In one implementation, the predetermined temperature maycorrespond to a cure temperature of the layup 50 (e.g., for a layup 50comprising a thermosetting resin matrix 53 (FIG. 7)). In anotherimplementation, the predetermined temperature may correspond to aconsolidation temperature of the layup 50 (e.g., for a layup 50comprising a thermoplastic resin matrix 53 (FIG. 7)). In alternativeaspects, the heating step (Block 270) may occur either before and/orafter the step (Block 260) of establishing a flow of fluid.

Examples of the disclosure may be described in the context of anaircraft manufacturing and service method 400, as shown in FIG. 10, andan aircraft 402, as shown in FIG. 11. During pre-production, theaircraft manufacturing and service method 400 may include specificationand design 404 of the aircraft 402 and material procurement 406. Duringproduction, component/subassembly manufacturing 408 and systemintegration 410 of the aircraft 402 takes place. Thereafter, theaircraft 402 may go through certification and delivery 412 in order tobe placed in service 414. While in service by a customer, the aircraft402 is scheduled for routine maintenance and service 416, which may alsoinclude modification, reconfiguration, refurbishment and the like.

Each of the processes of method 400 may be performed or carried out by asystem integrator, a third party, and/or an operator (e.g., a customer).For the purposes of this description, a system integrator may includewithout limitation any number of aircraft manufacturers and major-systemsubcontractors; a third party may include without limitation any numberof venders, subcontractors, and suppliers; and an operator may be anairline, leasing company, military entity, service organization, and soon.

As shown in FIG. 11, the aircraft 402 produced by example method 400 mayinclude an airframe 418 with a plurality of systems 420 and an interior422. Examples of the plurality of systems 420 may include one or more ofa propulsion system 424, an electrical system 426, a hydraulic system428, and an environmental system 430. Any number of other systems may beincluded.

The disclosed tooling assembly, system and method for manufacturing aporous composite structure may be employed during any one or more of thestages of the aircraft manufacturing and service method 400. As oneexample, the disclosed tooling assembly, system and method formanufacturing a porous composite structure may be employed duringmaterial procurement 406. As another example, components orsubassemblies corresponding to component/subassembly manufacturing 408,system integration 410, and or maintenance and service 416 may befabricated or manufactured using the disclosed tooling assembly, systemand method for manufacturing a porous composite structure. As anotherexample, the airframe 418 and the interior 422 may be constructed usingthe disclosed tooling assembly, system and method for manufacturing aporous composite structure. Also, one or more apparatus examples, methodexamples, or a combination thereof may be utilized duringcomponent/subassembly manufacturing 408 and/or system integration 410,for example, by substantially expediting assembly of or reducing thecost of an aircraft 402, such as the airframe 418 and/or the interior422. Similarly, one or more of system examples, method examples, or acombination thereof may be utilized while the aircraft 402 is inservice, for example and without limitation, to maintenance and service416.

The disclosed tooling assembly, system and method for manufacturing aporous composite structure are described in the context of an aircraft;however, one of ordinary skill in the art will readily recognize thatthe disclosed tooling assembly, system and method for manufacturing aporous composite structure may be utilized for a variety ofapplications. For example, the disclosed tooling assembly, system andmethod for manufacturing a porous composite structure may be implementedin various types of vehicles including, e.g., helicopters, passengerships, automobiles and the like.

Although various examples of the disclosed tooling assembly, system andmethod for manufacturing a porous composite structure have been shownand described, modifications may occur to those skilled in the art uponreading the specification. The present application includes suchmodifications and is limited only by the scope of the claims.

What is claimed is:
 1. A method for manufacturing a porous compositestructure comprising: positioning a green layup between a first toolingsurface and a second tooling surface, wherein said first tooling surfacecomprises a plurality of first perforations and said second toolingsurface comprises a plurality of second perforations; and establishing aflow of fluid through said plurality of first perforations, through saidlayup, and through said plurality of second perforations.
 2. The methodof claim 1 further comprising distributing said fluid by way of amanifold prior to flowing said fluid through said layup.
 3. The methodof claim 1 further comprising sealing a tooling assembly comprising saidfirst tooling surface and said second tooling surface prior to saidestablishing said flow of said fluid.
 4. The method of claim 3 whereinsaid establishing said flow of said fluid comprises fluidly couplingsaid tooling assembly with a fluid source.
 5. The method of claim 4wherein said fluid source is a vacuum source.
 6. The method of claim 1further comprising collecting said fluid after said fluid has flowedthrough said layup.
 7. The method of claim 1 further comprising heatingsaid layup during said establishing said flow of said fluid.
 8. Themethod of claim 1 wherein said flow of said fluid though said layupdefines a plurality of tortuous paths through said layup.
 9. A porouscomposite structure manufactured by the method of claim
 1. 10. A methodfor forming a plurality of tortuous paths in a green layup comprising aplurality of plies, each ply of said plurality of plies comprisingreinforcing fibers embedded in a resin matrix, said method comprising:supporting said layup; and while said layup is supported, flowing fluidthrough said layup to displace at least some of said resin matrix,thereby forming said plurality of tortuous paths in said layup.
 11. Themethod of claim 10 further comprising distributing said fluid by way ofa manifold prior to flowing said fluid through said layup.
 12. Themethod of claim 10 wherein said supporting said layup comprisespositioning said layup between a first tooling member and a secondtooling member.
 13. The method of claim 10 further comprising curingsaid layup after forming said plurality of tortuous paths in said layup.